Validator: add "gap between buildings"

[MKnight]

Miss a check similar to "overlapping buildings" the "gap between buildings" like in Osmose: ​http://osmose.openstreetmap.fr/de/map/#zoom=18&lat=50.112381&lon=8.683292&layer=Mapnik&overlays=FFFFFFFFFFFFFFFFFFFFT&item=0&level=1%2C2%2C3&tags=&fixable=

If that's to easy to implement (;)) additional add function to select gap-width.

Additional Infos: ​https://github.com/osm-fr/osmose-backend/blob/a47fe1ee75cd67951b46278fc1f506c82f8c1b9a/analysers/analyser_osmosis_building_overlaps.py#L106-L122
via:

(german): ​http://forum.openstreetmap.org/viewtopic.php?id=52717

[Aun Johnsen <lists@…>]

Lack of gap between buildings is not necessarily wrong (for example where I live, the outer wall of my house is part of the outer wall of my neighbour to the right, and the neighbour to the left), overlapping buildings on the other hand is most likely wrong. Another thing I have seen at times are buildings inside buildings, which are most definitely wrong.

[MKnight]

Aun: you are right, that that not _must_ be wrong, but it can be wrong (in most of the times is it) I think this check can be in the category "other" (not warnings).

you can give osmose a try for that, 95% of gap-errors there are wrong on the ground/map.

Dont understand your example, if "your" buildings are connected, then they have to be connected on the map too with no gap.

buildings inside buildings are wrong, yes, feel free to add an own feature request for that.

[Aun Johnsen <lists@…>]

MKnight: I have mapped my house and the neighbouring as accurate as possible, where they are visibly connected they are mapped sharing the same nodes, etc.

I agree that a check can be made to the validator, but put it rather in "information" than "warning" or "error", as my example are quite common, at least in denser cities.

On the other hand, it might be valid to explore (i.e. on the tagging@ mailing list) if it is wise to tag these buildings as individual polygons, or if rather a multi-polygon relation is on its place, though the validator should not give precedence in this until a decision in made from the community.

[Aun Johnsen <lists@…>]

I think building inside building already are warned about.

[MKnight]

i have checked the building inside building before my answer. (no warning) Maybe its broken since new josm-release. Will check that later.

[Aun Johnsen <lists@…>]

It is possible that the check is from an additional validator (external), I have a few external validators loaded.

[MKnight]

have checked building in building with older versions, no warnings. Do you want to open a new ticket for that?

P.s. (want to write me at ​https://www.openstreetmap.org/message/new/MKnight what (and how) external tools you use?)

[Klumbumbus]

The building inside building warning works as expected. You need to activate "geometry" in the validator tag checker settings.

[MKnight]

Replying to Klumbumbus:

The building inside building warning works as expected. You need to activate "geometry" in the validator tag checker settings.

Klumbumbus: thx, dunno why that was not activated here.

[mdk]

I think a gap between buildings is possible (normally wide enough that a huuman can pass).

But I found often buildings which only has one node together (see attachment). I have never seen two buildings which touch only in one point and habe a acute angle.

[mdk]

@MKnight: Can you append an example file where you expect a validator warning? Or is the ticket not longer relevant?

[MKnight]

Examples with one-node-together:
​http://osmose.openstreetmap.fr/de/map/#zoom=18&lat=49.291076&lon=6.877399&layer=Mapnik&overlays=FFFFFFFFFFFFFFFFFFFT&item=&level=1%2C2%2C3&tags=&fixable=
​http://osmose.openstreetmap.fr/de/map/#zoom=18&lat=49.418647&lon=6.840936&layer=Mapnik&overlays=FFFFFFFFFFFFFFFFFFFTT&item=&level=1%252C2%252C3&tags=&fixable=
​http://osmose.openstreetmap.fr/de/map/#zoom=18&lat=49.324613&lon=6.935860&layer=Mapnik&overlays=FFFFFFFFFFFFFFFFFFFT&item=&level=1%2C2%2C3&tags=&fixable=

zero-node-gaps:
​http://osmose.openstreetmap.fr/de/map/#zoom=18&lat=49.335995&lon=6.868176&layer=Mapnik&overlays=FFFFFFFFFFFFFFFFFFFTT&item=0&level=1%2C2%2C3&tags=&fixable=
and next in right of that, and next in south of that

[MKnight]

Not good examples?

[GerdP]

While it would be interesting to code such a test reg. performance I think it would just produce lots of messages for objects which are not really wrong, similar to the RightAngleBuildingTest. Mappers would be forced to add connections and maybe use Q hot key to create right angles again. In the end, all nodes and at least one way is modified for no visual improvement.